Here's what I use to load my webmin on my servers (which is firewalled away so only somebody with ssh access can see it):
ssh -l oli -L 9090:localhost:9090 my-server-ip
That connects me to the server and maps my local port 9090 to the server's P9090. I just browse at
http://localhost:9090/ and I can see the webmin.
If you're trying to connect to another device through your server, you don't really want to faff around with manual tunnel options.
ssh has a built-in SOCKS proxy mode. Run this:
ssh -D 9999 oli@my-server-ip
Then you tell your browser about the SOCKS proxy. Look under the network settings.
localhost as the server, port
9999. Remember this has to be under the setting for SOCKS. This is not a HTTP proxy.
Now when you browse, all the traffic goes through the ssh tunnel. This means if there's a device on the other end that only your server can reach, you can connect to that using its IP.
Note that DNS lookups and other network traffic won't go through the tunnel (AFAIK) so you need to connect to an IP if it makes a difference (which I suspect it will in this case)